Abstract
Mobile social applications that allow users to share presence, opinions and recommendations about places are spreading rapidly. Among these, check-in applications are becoming increasingly popular, but present some issues. In this paper we illustrate a system to exploit user's context to perform automatic check-in validation and suggestion. A description of the system architecture and its technical components is given, focusing on how raw and inferred context data (position, motion status, contacts proximity, etc.) are used to validate and suggest check-ins automatically.